No. 33–Questions and Answers

Q. I read in the newspaper about the Department of Natural Resources oyster project using bags of oyster shell to build artificial oyster reefs. How does the process work? The article also stated that your estuarium was working with students to try to improve on the department’s method, what are you and the students doing that’s different?

A. Some of information in this answer has been covered in previous columns but is worth repeating in a new construct to answer certain elements of the question that have not been covered.

An outgrowth of the SCDNR oyster project which began four years ago, the oyster restoration project and ongoing experiment being conducted by the Estuarium in partnership with students at Port Royal Elementary School is now in its third year. The following info is part of the orientation received by each year’s new group of 4th graders entering the program and will serve here to answer a portion of the question in this months column.

Oysters are bivalves. Bi means two and valve means shell. A bivalve is a creature with two shells. Clams are another kind of bivalve.

Some animals have live babies and others lay eggs. Oysters are among the many kinds of animals that live in water that reproduce by what is called spawning. Oysters spawn by squirting their eggs and sperm into the water and letting the water currents mix them together to fertilize the eggs.

Oyster eggs do not hatch directly into baby oysters with shells. There are what is called larval stages between the egg and the baby oyster with a shell. Think of a butterfly egg that hatches into a caterpillar that then becomes a butterfly. The caterpillar is the larval stage of the butterfly.

Oyster larva float in the water for two to three weeks while they go through their larval stages. The last larval stage is called pediveliger. Pedi means foot and veli means veil. The pediveliger can crawl with its foot or swim with its velum, which is kind of like a sail. The velum is covered with tiny hairs called cilia which help the larva swim and also catch food. After the pediveliger comes the post-larva called spat. Post means after and spat is what we call a baby oyster that has a chance grow up.

The pediveliger’s job is to find a permanent home and it can’t just land anywhere and expect to survive. If it lands in mud and can’t get out it will die. It needs to land on something hard where it will make a kind of cement to lock itself in place and finally become a spat. The spat will begin to grow and if it’s in a good place may one day become a big oyster.

Have you noticed how most oysters are stuck together in clusters. That’s because oysters are hard and make a good place for pediveligers to land and change into spat. Most clumps have oysters of different sizes because they were spawned in different years. The biggest are the oldest with younger oysters attached to them.

Once the students have classroom understanding of the oyster spawning process, the orientation proceeds with an introduction to the tangible elements of the experiment in the field where they observe the work of previous years and literally get their feet wet for what is to come.

With ensuing monthly forays to the test site through summer into early winter, the students record a set of observations of the various elements of the field experiment from which they draw conclusions for their end of year assessment.

With each year’s group of students following on the work of previous years and tasked with, through their observations, thinking of ways to either add new experimental elements to be tested or improve the project as a whole, the project itself continues to evolve.

One of the more personally satisfying aspects of the project lays in playing a role in young minds developing skills of close observation and creative thinking that will serve them well in the future. On behalf of the Estuarium board, I thank PRES principal Kay Keeler, staff, and PTO for giving us the opportunity, through the oyster project and other programs, to be an active player in the educational life of their children.